How to provide translations for a WordPress TinyMCE plugin?

I know that I can get my translations into JavaScript doing:

    $MyTranslations = array(
        'translation1' => __("Some String 1", "MyTranslations"),
        'translation2' => __("Some String 2", "MyTranslations")
    );
    wp_localize_script( 'jquery', 'my_translations', $MyTranslations );

But looking at some of WordPress TinyMCE plugins they use calls like this:

{
title : ed.getLang('advlink.link_desc'),
...
}

How is WordPress getting their translations into getLang()? Am I supposed to do it this way or do I just use my first bit of code and access the variables directly like:

{
title : my_translations.translation1,
...
}

Answers:

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Method 1

Use the filter 'mce_external_languages'. From wp-includes/class-wp-editor.php:

The following filter loads external language files for TinyMCE plugins.
It takes an associative array ‘plugin_name’ => ‘path’, where path is the
include path to the file. The language file should follow the same format as
/tinymce/langs/wp-langs.php and should define a variable $strings that
holds all translated strings.
When this filter is not used, the function will try to load {mce_locale}.js.
If that is not found, en.js will be tried next.

$mce_external_languages = apply_filters('mce_external_languages', array());

I would just use a copy of wp-includes/js/tinymce/langs/wp-langs.php … and drop that superfluous mce_escape() in favour of the original esc_js().

Sample file:

<?php # -*- coding: utf-8 -*-

$strings = 'tinyMCE.addI18n(
    {' . _WP_Editors::$mce_locale . '.extrastrings:
        {
            helloworld: "' . esc_js( __( 'Hello World', 'my_plugin_text_domain' ) ) . '",
            foobar: "' . esc_js( __( 'Foo Bar', 'my_plugin_text_domain' ) ) . '"
        }
    }
)';

In your plugin you just use:

add_filter( 'mce_external_languages', 'wpse_44785_add_tinymce_lang', 10, 1 );

function wpse_44785_add_tinymce_lang( $arr )
{
    $arr[] = 'full_path_to_lang_file.php';
    return $arr;
}

To access the new strings in JavaScript use for example:

title : ed.getLang('extrastrings.helloworld')

Method 2

Your sample file gaved me an error (undefined . before extrastrings).
So i changed code:

<?php # -*- coding: utf-8 -*-

$strings = 'tinyMCE.addI18n( "' . _WP_Editors::$mce_locale . '.extrastrings", {
    title: "' . esc_js( __( 'Shortcodes', 'm7' ) ) . '",
    popup_title: "' . esc_js( __( 'Шорткоды', 'm7' ) ) . '"
} )';

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0